Diversity and Value of Extant Hawaiian Sugarcane (Saccharum officinarum [L.]) Cultivars

Sugarcane is one of the most economically important crops with particular cultural and economic significance in the Hawaiian Islands. The historical influence of sugarcane in Hawai‘i tends to overshadow the fact that Native Hawaiians cultivated dozens of unique varieties of sugarcane for almost a millennium before the arrival of Europeans. The objective of this study was to characterize the genetic and phenotypic diversity of sugarcane to reexamine the relationships between traditional Hawaiian sugarcane varieties and heirloom cultivars from elsewhere in the Pacific. To this end, a morphological assessment utilizing 95 phenotypic characteristics of 53 extant cultivars held in ethnobotanical collections was conducted, along with genetic assignment using 6,570 polymorphic SNP markers on 156 diverse varieties. In investigating distinct traditional cultivars of extant sugarcane collections in Hawai ‘i as “Hawaiian,” our findings demonstrated the need for intimate knowledge and relationships with accessions in order to make meaningful interpretations of genetic and phenotypic data. Based on over 15 years of involvement with the heirloom Hawaiian canes and the traditional and contemporary uses, we demonstrated and discussed the unique value of these cultivars, and their potential to contribute to economics, sustainability, and the preservation of cultural heritage.